Trying to solve the LFX WOT Restriction

[Vaddy]

As some or maybe not a lot of people know the LFX has a wide-open throttle restriction until 4k rpms from a dead stop. I wanted to create this thread to kind of spread a bit of awareness and try to solve this mystery that has been going on for a decade now. For the people who don't know, if you do any bit of datalogging, you will notice that your accelerator pedal is 100% but the throttle would be only open for 70% for example.



Until it reaches around 4k rpms, that's when it hits close to 100%



So why am I bringing this up? Well because doing some experimenting with tuning for drag racing, I made an interesting discovery.

Here you can see, on my regular tune (Blue line), the throttle is at 92% and after some VVT tuning changes (Red line), it goes all the way down to 82% at the same RPM.




Basically, the red line is with no VVT, the cam is locked at 0 degrees in HP Tuners, so this tells me one of 2 things. The higher the retard for the intake cam specifically, the higher the throttle position or which is more likely, because you are getting more torque from having the VVT intake cam, the more the throttle opens.

I believe it is the second option because increasing the virtual torque tables in HP tuners increased the throttle opening, but because the car has VVT, you have to increase the values for each cam angle.



Almost the same tune up but with the virtual torque tables increased. The issue is not completely solved, but I wanted to share this info because everywhere I searched, no one was covering this. If anyone knows info, that would be great.

Also wanted to share, from the top, even though both tunes almost have the same torque. At the bottom, there's a difference in throttle opening. The only difference between the two is the exhaust cam being zerod out for the blue line. I don't think this had to do with VVT itself but because I didn't change the virtual torque values for the exhaust cam angle.